Engines to be mounted on vehicles include a natural air intake type engine for taking in air due to the pressure difference between the inside and the outside of the combustion chamber, and an engine with a supercharger where intake air is forced into the combustion chamber.
The engine with a supercharger is conventionally provided with an air intake structure as shown in FIG. 7. The intake structure includes an air cleaner 102 and a first intake pipe 104 with one end thereof connected to the air cleaner. The other end of the first intake pipe 104 is connected to a supercharger 106, which connects to an exhaust manifold (not shown) arranged at the exhaust side of the engine. One end of a second intake pipe 108 is connected to the supercharger 106. The other end of the second intake pipe 108 is connected to an intercooler 110. One end of a third intake pipe 112 is connected to the intercooler 110. The other end of the third intake pipe 112 is connected to a throttle body 116 which connects to an intake manifold 114 arranged at the intake side of the engine.
In the known air intake structure of FIG. 7, the second intake pipe 108, the intercooler 110 and the third intake pipe 112 are arranged in such a manner as to take a long way (i.e., a long path or distance) around the engine from the supercharger 106 arranged on the exhaust side of the engine to the throttle body 116 arranged on the opposite, i.e. intake side of the engine. Since the intake pipes 108 and 112 define a long distance around the engine from the supercharger 106 to the throttle body 116, there are disadvantages in that the intake layout is complicated, the compact configuration of the engine is obstructed, and the engine response during a transient state is deteriorated due to the long path length from the supercharger 106 to the throttle body 116.
Also, in the air intake structure shown in FIG. 7, there is a further problem in that the intercooler 110 does not have much structural support and may be moved or loosened by engine vibration. In order to increase the support rigidity of the intercooler 110, an intercooler support member (not shown) must be installed and supported on the engine side. This is a disadvantage in that the cost is increased due to increasing the number of parts and the number of assembling processes.